I'm going to be using my machine for gaming, as well as photo editing and video editing (going to college)

If you could suggest (and maybe even link to) some good replacements for the least amount of money, seeing as I'm expecting around £200-£300 from selling my laptop and I'm going to work for the rest of it

Well it really isn't. I don't want to insult your hardware but the original Phenom's aren't very good. At that time AMD was officially over a generation behind Intel's Yorkfield chips. On top of that, the B2 and BA stepping Phenom's had the TLB bug which was fixed, but at the cost of 10% of computing performance.